Derived UV-Vis Absorbance Spectra for Facile Analysis of Optically Dense Samples

The UV-vis absorption bands of optically dense samples are broad, overlapped, saturated, nonlinear, and have minor peaks suppressed; often, the minor peaks are representative of the analytically noteworthy lowest-energy electronic transitions (S₀ to S₁). Conventional UV-vis methods limit the accurate analysis of optically dense samples. This study introduces the use of derived UV-vis absorbance spectra (A _D = A × 10^-A ) as a tool for the facile analysis of highly absorbing optically dense samples in their original form, without any pretreatment or alteration. The derived UV-vis absorbance spectrum (A _D) is obtained by multiplying the function 10^-A with the absorbance data (A) of the sample. The A _D spectral profile rises in the interval 0.001 < A < 0.434 due to the increasing function A, then decreases in the interval 0.434 < A < ∞ due to the function 10^-A . A maximum is obtained at 0.16 in the A _D spectrum, representing an absorbance of 0.434. The A _D spectra amplify obscured spectral features, behave well in the linear regime of the Lambert-Beer law, suppress noise- and saturation-dominated regions of the original absorbance spectra, and eliminate the need for dilution (which may introduce errors) or for specialized cuvettes with reduced path lengths. Especially, the A _D peak at 0.16, corresponding to a 0.434 absorbance value, serves as a robust and quantifiable spectral descriptor.